Modeling and experimental analysis of the vibrations in hard disk drives

A combined methodology, based on dynamic modeling and experimental measures, is used to study the vibrations in hard disk drives, in a frequency range up to 1 kHz. A lumped parameter model of the disks/spindle assembly is developed, where only the disk modes coupled with the spindle motion are retained. The proposed model has been validated by comparison with experimental results. Using the model, the sources of axial and radial vibrations measured in a single plate commercial hard disk drive have been explained. Among them are the disk structural resonances, due to compliances in bearings and disks, displacements of the center of mass from the rotation axis and unbalanced magnetic forces. On the other hand, no evidence has been found of the influence of torque disturbances on the measured vibrations.